Super-drawing polyster filaments after application of a di-ester of apolyalkylene glycol

ABSTRACT

R1-COO-AH, R1-COO-A-CO-R2, R1-O-AH, OR R1-O-A-CO-R2   WHEN A MELT-ADHESION PREVENTING AGENT SELECTED FROM COMPOUNDS EXPRESSED BY THE FLOLLOWING FORMULAS 1 TO 4 IS APPLIED TO SUBSTANTIALLY AMORPHOUS, MELT-SPUN, UNDRAWN SYNTHETIC LINEAR POLYESTER FILAMENTS IN AN AMOUNT OF AT LEAST 0.05% BY WEIGHT BASED ON THE WEIGHT OF THE FILAMENTS. AND THEN THE FILAMENTS ARE SUPER-DRAWN, MELTADHESION AMONG FILAMENTS, WHICH IS INEVITABLY CAUSED TO OCCUR IN CONVENTIONAL SUPER DRAWN METHODS, CAN BE COMPLETELY PREVENTED:   D R A W I N G

NOV. 6, 1973 YUTAKA HIRANQ ETAL 3.710361 SUPER-DRAWING POLYESTER FILAMENTS AFTER APPLICATION OF A DI-ESTER OF A POLYALKYLENE GLYOOL Fileql Nov. 19, 1970 United States Patent Oliice 3,770,861 UPER-DRAWING POLYESTER FILAlVIENTS s AFTER APPLICATION OF A DI-ESTER OF A POLYALKYLENE GLYCOL Yutaka Hirano, Tadayuki Yamane, and Syozr Matsumoto,

Kurashiki, Japan, assignors to Kg'u'aray Co., Ltd., Kurahiki C Okayama Prefecture apan s l iled Nov. 19, 1970, gr. 110 9093 1969 C1 ms riority, application apan ov.

31 403,741; Dec. 25, 1969, nt/1,097

Int. Cl. B29c 17/02 US. Cl. 264-430 2 Claims ABSTRACT OF THE DISCLOSURE and m-o-a-ii-nz This invention relates to polyester filament bundles and a process for the preparation of the same. More specifically, this invention relates to super-drawn polyester filament bundles free of melt-adhesion among filaments and to a process for the preparation of such polyester filament bundles.

It is known that there is a phenomenon called superdraw which is seen peculiarly only in filaments or films of synthetic linear polyesters. The super-draw is a phenomenon that filaments or films composed of asmelt-extruded amorphous synthetic linear polyesters are made only morphologically thin without any accompaniment of substantial molecular orientation or crystallization. In contrast to this phenomenon, the drawing accompanied by molecular orientation and crystallization 1s called natural draw or merely drawing. The superdraw may be caused to occur only by stretching filaments or films composed of as-melt-extruded amorphous synthetic polyesters under suitable temperature and tension conditions. Conditions causing the super-draw are described in, for instance, US. Pat. 2,578,899. The superdraw, when combined with the ordinary dram'ng, can give such a high ratio stretching as will not be attained by the ordinary drawing alone. The above cited patent teaches processes for conducting the drawing at a very high draw ratio by utilizing the super-draw.

I 3,770,861 Patented Nov. 6, 1973 Thus the super-draw is a phenomenon well known in the literature and many advantages are expected by utilizing this phenomenon in the steps of spinning and stretching synthetic linear polyester filaments. As a matter of fact, there has been no sign of industrial utilization of the super-draw in the art. The greatest reason for avoidance of industrial utilization of the super-draw is that melt-adhesion is caused among filaments during the super-draw. The super-draw ought to be regarded as a kind of flow phenomenon, and while filaments are being deformed by the super-draw, if filaments are contacted with one another, they are allowed to adhere to one another at contact points and resulting filament bundles are in the so-called fixedly bonded state. When such melt-adhesion is caused to occur, in an extreme case multifilaments are so converted as if they were one monofilament. The melt-adhesion of filaments caused during the super-draw step may be partially released by shearing stress or bending stress imposed on filaments during subsequent steps, for instance, the ordinary drawing or crimping step, but the once formed melt-adhesion cannot be completely removed without incurring substantial damage to filaments. When knitted or woven fabrics are made from such melt-adhered filaments, the touch or luster of the fabrics is extremely bad. In case the spinning step is required in the latter stage as in staple fibers, the meltadhesion among filaments causes occurrence of neps. As described above, the melt-adhesion among filaments causes various troubles in the actual operation. Accordingly, in order to utilize the super-draw industrially, it is by all means necessary to prevent occurrence of meltadhesion among filaments. However, in the conventional techniques, whenever the super-draw is conducted, the melt-adhesion is inevitably caused to occur among filaments. There has not been known a method of preventing eifectively the occurrence of the melt-adhesion.

We have made research with a view to developing a super-draw process in which occurrence of melt-adhesion among filaments can be prevented, and as a result, we have arrived at this invention.

In accordance with this invention, there is provided a process for the preparation of synthetic linear polyester filament bundles substantially free of melt-adhesion among filaments and Without any substantial molecular orientation, which comprises super-drawing undrawn, substantially amorphous synthetic linear polyester filaments obtained by melt-spinning a synthetic linear polyester in which at least 80 mole percent of the recurring units are ethylene terephthalate units, and thereby making the filament size finer only morphologically without any substantial orientation; wherein at least one compound selected a from the group consisting of (1). Compounds expressed by the following formula:

in which n, m and 12 each are integers not less than 1; and R is an alkyl, aralkyl or alkylaryl group of 226 carbon atoms, a

wherein R and A are as defined above, and

(IV) Compounds expressed by the following formula:

R1OA-i%-Rz (IV) wherein R R and A are as defined above; is applied to the filaments in an amount of at least 0.05% by weight based on the weight of the filaments, and thereafter the filaments are super-drawn.

By the above-mentioned process of this invention, there is provided a super-drawn filament bundle comprising a plurality of filaments having no substantial molecular orientation and no substantial melt-adhesion among them, such filaments being composed of a synthetic linear polyester in which at least 80 mole percent of the recurring units are ethylene terephthalate units, and, applied on the surfaces of the filaments, at least 0.05% by weight based on the weight of the filaments of at least one compound selected from the group consisting of (1) Compounds expressed by the following formula:

R C-O-AH wherein A stands for a group (CH CH O),,,

CH: CH: (CHA JHO)I or [(CH2cH20)n(CHiHO)m]p in which n, m and p each are integers not less than 1; and R is an alkyl, aralkyl or alkylaryl group of 2-26 carbon atoms,

(II) Compounds expressed by the following formula:

Rlo-A-c'i-Rr (IV) wherein R R and A are as defined above.

As long as at least one compound selected from compounds (I) to (1V) is applied to filaments in an amount of at least 0.05% by weight based on the weight of the filaments, the filaments may have known oiling agents additionally applied thereto. The presence of such agents does not inhibit or lower the effect of preventing the meltadhesion.

This invention will now be detailed by accompanying drawings.

'FIG. 1 is a photograph showing asuper-drawn polyester filament, bundle prepared in accordance with the process of this invention, in which melt-adhesion is not caused to occur among filaments. FIG. 2 is another photograph showing a'super-drawn polyester filament bundle obtained by the conventional method, in which melt-adhesion is brought about among filaments.

The polyester filament to be used in the process of this invention is composed of a homopolymer of ethylene terephthalate or a eopolyester comprising at least mole percent of ethylene terephthalate units. As the comonomer there may be used one or more of dibasic acids such as adipic acid, sebacic acid, isophthalic acid, diphenyl dicarboxylic acid and naphthalene dicarboxylic acid; oxy acids such as oxybenzoic acid; and glycols such as diethylene glycol, propylene glycol, neopeutyl glycol, pentaerythritol and polyethylene glycol monomethyl ether.

In the specification and claims, the term filament bundle is used to mean a filament bundle comprising at least two filaments."

Specific examples of compounds (I) and (II) to be used in the process of this invention for preventing occurrence of melt-adhesion among filaments during the super-drawing step include monoand di-esters of polyalkylene glycols such as polyethylene glycol, polypropylene glycol and block or random copolymers of polyethylene glycol and polypropylene glycol, with acids such as caproic acid, caprylic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, nonadecanoic acid, melissic acid, laurolanic acid, oleic acid, elaidic acid, linoleic acid, butyl benzoic acid, nonyl beuzoic acid and benzene propionic acid.

Specific examples of compounds (III) are monoethers of polyethylene glycol, polypropylene glycol or a block or random copolymer of polyethylene glycol and polypropylene glycol, with caproyl alcohol, heptyl alcohol, capryl alcohol, undecyl alcohol, lauryl alcohol, myristyl alcohol, pentadecyl alcohol, cetyl alcohol, stearyl alcohol, nonadecyl alcohol, eicosanol, 3-hexenol-l, Z-heptenol-l, IO-undecenol-l, ll-dodecenol-l, lZ-tridecenoI-l, oleyl alcohol, elaidyl alcohol, linoleyl alcohol, linolenyal alcohol, butyl phenol, nonyl phenol or benzene ethanol.

Specific examples of compounds (IV) are esterified products of compounds (III) with caproic acid, capric acid, caprylic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, nonadecanoic acid, melissic acid, laurolanic acid, oleic acid, elaidic acid or linoleic acid. The filaments may contain additionally known additives such as delustering agents, i.e., titanium oxide, weather-resistant agents, heat-resistant agents, color stabilizers, i.e., phosphorus compounds, antistatic agents, fluorescent agents, viscosity stabilizers, i.e., boron compounds, etc.

One preferred embodiment of the process of this inven tron comprises applying to undrawn, substantially amorphous, melt-spun synthetic linear polyester filaments at least one compound selected from compounds (I) to (IV) in an amount of 0.05% by weight based on the weight of the filaments, heating the filaments in a heated liquid bath of water, ethylene glycol or polyethylene glycol or a heated gas bath of steam or air, or with use of a customary heating device used in the filament processing, such as a hot roll or a solid heater, thereby raising the temperature of the filaments to a level suitable for causing the super-draw, and stretching the filaments to super-draw the same.

The preferable temperature in the super-draw is C. in the case of using filaments of polyethylene terephthalate. In the case of copolyesters, a slightly lower temperature is adopted.

The application of such compounds (I) to (IV) is accomplished by a method known heretofore such as roller-touching or spraying one compound selected from compounds (I) to (IV) of a mixture of two or more compounds selected from compounds (I) to (IV) without diluting it. It is also possible to use an aqueous solution or solvent solution containing at least one compound selected from compounds (I) to (TV) at a concentration of (Ll-20% by weight, preferably 0.5-5 by weight. In

case the melt-adhesion preventing compound is applied to the filaments in the form of a solution, it is preferred that the super-draw is effected after the filaments have been air-dried or dried by heating to substantially, anhydrous state.

According to the above-mentioned process of this invention, melt-adhesion is not caused to occur during the super-drawing step, and it is possible to obtain end products excellent in touch and luster. Further, when staple fibers prepared in accordance with the process of this invention are subjected to the spinning processing, it is possible to conduct the spinning processing without any trouble.

In the process of this invention, the stretching for the super-draw is conducted at a stretch ratio of 50 to 5000%, preferably 100 to 3000%.

The undrawn polyester filament bundle which has been thus super-drawn, is then subjected to an ordinary drawing to cause orientation and crystallization of the filaments, whereby filaments of practical utility can be obtained. If desired, these filaments are subjected to ordinary proc essing treatments such as crimping, heating and dyeing treatments.

In the process of this invention, as it is possible to accomplish the super-draw of a high stretch ratio without causing melt-adhesion among filaments, it is possible to easily manufacture filaments of a very fine denier, e.g., less than 0.1 denier. It is difiicult to manufacture filaments of such fine denier by customary spinning and drawing methods. Still further, the process of this invention has the following great advantage:

In all the melt-spinable polymeric filaments, there is a certain limit of the draw ratio in the natural drawing, beyond which the drawing is not possible without ruptures or breakages of filaments. In general, such critical draw ratio is in the range from 300 to 900% of the original filament length. Because of such limit of the draw ratio, it is impossible to increase the draw ratio excessively. Accordingly, when filaments varying in denier within a broad range are required for the manufacture of end products as in the actual industrial production, it is impossible to supply all the filaments of deniers diifering within a broad range, that are required for the manufacture of end products, from spun raw filaments of only one denier (filaments which have been melt-spun but not drawn as yet). Therefore, in the actual industrial production, 'it is generally necessary to prepare several kinds of raw filaments differing in denier. In order to provide raw filaments differing in denier, it is necessary to change the melt-spinning conditions depending on the desired denier. At every change of the melt-spinning conditions, considerable time is spent for arrangement of the meltspinning apparatus or other equipment, and flocks are formed at every change of the operation conditions, with the consequence that the manufacturing efiiciency is lowered and waste of material is not avoided. On the other hand, in the process of this invention, it is possible to manufacture undrawn polyester filaments having various kinds of deniers suitable for the preparation of end products by fixing the melt-spinning conditions while changing only the super-draw conditions appropriately. Accordingly, in accordance with the process of this invention it is quite unnecessary to change the melt-spinning conditions so as to obtain several kinds of filaments differing in denier.

Therefore, the spinning may be conducted under fixed conditions, with the result that the above-mentioned inevitable defects of the conventional techniques, such as lowering of the manufacturing efficiency and waste of material, can be overcome by the process of this invention. Consequently, when the process of this invention is adopted, the spinning and drawing can be conducted with great economical advantages.

Further, in the process of this invention, it ispossible to manufacture very easily filaments of the same denier l filaments.

3 jcons'tant level.

but different in the elongation by changing the super-draw ratio afid' natural draw ratio while maintaining the overall" draw ratio of the super-drawing and natural drawing at 21 Still further, the super-draw technique of this invention may be applied to the preparationof highly shrinkable References have been heretofore made mainly to the spinning and drawing of filaments, but the super-draw technique of this invention may be applied to the preparation of polyester films, when two or more undrawn polyester films are overlapped and then subjected to the super-drawing treatment.

The determination as to whether melt-adhesion is caused to occur among the super-draw filaments may be done by the naked-eye observation or the feeling test, but the determination may be effected by the following method:

A loop of about 25 cm. circumference is formed from a multifilament of 250 denier/ 18 filaments obtained by super-drawing at a draw ratio of 2 an undrawn polyester multifilament of 500 denier/ 18 filaments in a boiling water maintained at C. A poise of 50 mg. is suspended from an optional point of the loop and it is supported at the point opposite to the point from which the poise is suspended. The length (D of the long axis of the loop deformed to an ellipse is measured. Then the poise is replaced by another poise of 2.5 g. and the length (D of the long axis of the loop is similarly measured. When there is no melt-adhesion among filaments, the filament bundle is flexible, and the D value is relatively large, but when there is melt-adhesion among filaments, the filament bundle is rigid, and the filament bundle exhibits a resistance against stretching by the light weight poise of 50 mg., with the result that the D value is rela tively small. In the case of the poise of 2.5 g., the filament bundle exhibits an almost constant D value regardless of the presence of absence of melt-adhesion among filaments. Accordingly, in the present specification, the meltadhesion index K expressed by the formula K=D /D is adopted as a criterion indicating the degree of meltadhesion.

In super-drawn filaments having a melt-adhesion index K of 0.88 or less, melt-adhesion is extreme and even after such filaments are subjected to the ordinary drawing, it is confirmed by the naked-eye observation or the feeling test that melt-adhesion remains among filaments. In order to obtain a filament bundle in which melt-adhesion is completely absent after ordinary drawing, it is desired that the filament bundle, which has been superdrawn but not subjected to the ordinary drawing, has a melt-adhesion index K of greater than 0.88, preferably at least 0.9.

This invention will now be detailed by referring to examples, but this invention is not at all limited by these examples.

EXAMPLE 1 By way of comparison, Table 1 also shows results of comparative runs (runs Nos. 19 to 25) in which the above procedures were repeated by employing conventional oiling agents. Run No. 18 illustrates an embodiment where a mixture of the melt-adhesion preventing agent of this invention and a conventional oiling agent was used.

TABLE 1 Amount of applied Run No. Applied agent agent 1 value Touch 0. 25 0. 96 Q 0. 23 0. 95 Q 0. 19 0. 94 O 4 0. 0.94 G G 0. 14 O. 92 O CzH4C 0 0 (62114011511 7 Ci2H250(C2H40)sH 0.14: 0.96 (D 0.20 O. 94 O 0. l9 0. 95 Q 0.32 O. 97 G 0. 27 0.93 O

0. 30 0. 92 O O (CzHsOhH 021140 (CzHrOls 15 C12H250(C2H40);0COC17H35 0.14 0.95 O 16.. C1zH250(C3HeO) oCOC 1Hz3 0.20 0.96 (D C5H11 O (C2 )30C 0 CuHza CnHzaCOO(C2H40)1uCOCnH2a HO(C2H40)5 0 (1:1 mixture) 18 \P% 0. 22 U. 95 Q U 0. 81 X 0. 18 0. 81 X 0. 27 O. 83 X 0. 27 0. 82 X 23 HO(CzH40)5 O 0.19 0.85 A

(312E250 ONa 24 CIQHQSOSOQNE. O 21 0. 82 X 25 IC15H35N(CH3):4]CI* 0. 18 0. 84 X 1 Percent by weight.

EXAMPLE 2 TABLE 2 K value Amount 0! Polyoxy- Polyoxy applied agent ethylene ethylene (percent by weight) laurate lanryl ether As is seen from the results shown in Table 2, in order to obtain filament bundles free of melt-adhesion, it is necessary that the amount of either polyoxyethylene laurate or polyoxyethylene lauryl ether applied is at least 0.05% by weight.

EXAMPLE 3 To the same undrawn polyethylene terephthalate filament bundle as used in Example 1 0.30% by Weight of polyoxyethylene (n=40) dilaurate was applied. Then the filament bundle was dried and super-drawn at a draw ratio of 2 in a longitudinal air furnace of 1 in. length maintained at 160 C. while preventing the filament bundle from having a contact with the furnace wall. The melt-adhesion index K of the resulting super-drawn filament bundle was 0.92. Thus it was confirmed that when the super-drawing is conducted by employing a heating medium other than a liquid bath, the process of this invention can effectively prevent occurrence of melt-adhesion among filaments.

The so super-drawn filament bundle was then subjected to the drawing accompanied by necking at a draw ratio of 4.7 with use of a hot pin (one turn) maintained at C. and a hot plate maintained at C. A polyester filament bundle tree of melt-adhesion and excellent in touch was obtained. The resulting filament bundle was of 54 denier/ 18 filaments and characterized by a tenacity of 4.4 g./d., an elongation of 32% and a Youngs modulus of 76 g./d.

The above run was repeated by using polyoxyethylene (11:8) lauryl ether instead of the above pol'yoxyethylene dilaurate and changing the amount of agent applied to 0.25% by weght. The melt-adhesion index K of the resulting super-drawn filament bundle was 0.95. This superdrawn filament bundle was subjected to the drawing accompanied by necking at a draw ratio of 4.5 with use of a hot pin (one turn) maintained at 90 C. and a hot plate maintained at 140 C. As a result, a filament bundle of 56 denier/18 filaments which was free of melt-adhesion EXA E To the same undrawn polyethylene terephthalate filament bundle as used in Example 1 0.36% by Weight of polyoxyethylene (n= l4) .laurate was applied, and the filament bundle was dried and then super-drawn at a draw ratio of 2 by winding the filament bundle by two turns on an embossed rotary roll maintained at 120 C. The melt-adhesion index Kof the resulting super-drawn filament bundle was 0.90. This super-drawn filament bundle was subjected to the necking-drawing at a draw ratio of 4.9 in the same manner as in Example 3 with use of a hot pin maintained at 90 C. and a hot plate maintained at 140 C. As a result a filament bundle of 52 denier/18 filaments'which was free of melt adhesion and excellent injtouch' and had a tenacity of 4.7 g./d., an elongation of 29% and a Youngs modulus of 85 g./d. was obtained.

Ihe above run was repeated by using polyoxyethylene (n=12) 'nonylphhen'ol instead of the above polyoxyethylene laurate and changing the amount of agent applied to 0.40% by weight. The melt-adhesion index K of the resulting super-drawn filament bundle was 0.96.. This super-drawn filament bundle was subjected to the neckingdrawing at a draw ratio of 4.7 in the same manner as in Example, 3 with use of a hot pin maintained at 90 C. and a hot plate maintained at 140 C. As a result, a drawn filament bundle of 53 denier/ 18 filaments which was free of melt-adhesion and excellent in touch and had a tenacity of 4.5 g./d., an elongation of 35% and a Youngs modulus of 80 g./d. wasobtained.

1, EX P To an undrawn filament bundle of 500 denier/ 18 filaments composed of a'copolyethylene terephthalate (intrinsic viscositiy=0.61) copolymerized with 5 mole percent of isophthalie acid, 0.27%. by weight of polyoxyethylene (rt-=10) stearate wasadded, and then the filament bundle was dried and super-drawn at a draw ratio of 2 in hot water maintained at 100 C. The melt-adhesion index K of the resulting super-drawn filament bundle was 0.95. Then this super-drawn filament bundle was subjected to the ordinary drawing at a draw ratio of 4.0 in a bath of water maintained at 80 C. and shrunk by 12% at 120 C. Then '10 to 15 crimps per 25.4 mm. were given to the filament bundle by means of a box-type stufier crimper, and the crimped filament bundle was cut to about 51 mm. staple fibers. The resulting staple fibers were characterized by a size of 3.9 denier, a tenacity of 3.8 g./d., an elongation of 39% and a Youngs modulus of 42 g./d.

EXAMPLE 6 To an undrawn filament bundle of 5050 denier/310 filaments composed of a copolyethylene terephthalate (intrinsic viscosity=0.58) copolymerized with 1.0 mole percent of polyethylene glycol monomethyl ether (having a molecular weight of 2000) and 0.25 mole percent of pentaerythritol, 0.23% by weight of polyoxyethylene (n=l) dilaurate was added, and the filament bundle was allowed to stand at room temperature for 24 hours; to dry. Then the filament bundle was super-drawn in hot water maintained at 100 C. at a draw ratio of 1.5, 2.5 or 5. In each case, a polyester filament bundle free of melt-adhesion among filaments was obtained. Then the so super-drawn filament bundle was subjected to the ordinary drawing at a draw ratio of 3.0 and 10 to 15 crimps per 25 .4 mm. were imparted to the filament bundle by means of a stufler crimper, following which the filaments bundle was heat-treated at 130 C. for minutes and cut into about 51 mm. staple fibers. The properties of the resulting staple fibers are shown in Table 3.

if; rAn'Ln's. .Qjjg

. Draw Draw ratio ratio at Elonga-- Youngs V at superordinary -Tenacity -tion modulus l drawing drawing Denier .ld.) (percent) (g./d.)

In the subsequent step of spinning these staple fibers, no operational trouble occurred.

EXAMPLE 7 To an undrawn filament bundle of 3600 denier/200 filaments composed of a copolyethylene terephthalate (intrinsic viscosity of 0.57) copolymerized with 1.0 mole percent of polyethylene glycol monomethyl ether (having a molecular weight of 2000) and 0.25 mole percent of pentaerythritol, 0.25% by weight of polyoxyethylene (n: 12) nonylphenol ether was added, and the filament bundle was allowed to stand at room temperature for 24 hours to dry. Then the filament bundle was superdrawn in hot water maintained at 98 C. at a draw ratio of 3 or 6. In each case, a filament bundle free of meltadhesion was obtained. The section of the so obtained multi-filament bundle is shown in a scanning electromicroscopic photograph of FIG. 1.

The super-drawn filament bundle was subjected to the ordinary drawing at a draw ratio of 3.6 or 2.4 in a bath of hot water maintained at C., and 10 to 12 crimps per 2.54 mm. were imparted to the filament bundle by means of a stulfer crimper. Then the crimped filament bundle was heat-treated at 130 C. for 5 minutes and cut into about 51 mm. staple fibers. The properties of the resulting staple fibers are shown in Table 4.

TABLE 4 Draw Draw ratio ratio at Elonga- Youngs at superordinary Tenacity tion mo dulns drawing drawing Denier (g. /d.) (percent) (g. /d)

During the subsequent step of spinning these staple fibers, any operational trouble was not caused to occur.

EXAMPLE 8 To an undrawn filament bundle of "5050 denier/310 filaments composed of copolyethylene terephthalate (intrinsic viscosity=0.58) copolymerized with 1.0 mole percent of polyethylene glycol monomethyl ether (molecular weight=2000) and 0.25 mole percent of pentaerythritol, 0.55% by weight of a 1:9 mixture of polyoxyethylene (n=l0) lauryl ester and diethylene glycol butyl ether was applied. The filament bundle was allowed to stand at room temperature for 8 hours and super-drawn at a draw ratio of 2 in hot water maintained at 100 C. A polyester filament bundle free of melt-adhesion was obtained. This super-drawn polyester filament bundle was subjected to the ordinary drawing at a draw ratio of 4.0 with use of a bath of water maintained at 80 C. Then 10 to 15 crimps per 25.4 mm. were imparted to the drawn filament bundle with use of a stuflFer crimper, and the crimped filament bundle was heat-treated at C. for 5 minutes and cut into about 51 mm. staple fibers. The resulting polyester staple fibers were characterized by a size of 2.7 denier, a tenacity of 3.8 g./d., an elongation of 42% and a Youngs modulus of 48 g./d. During the subsequent step of spinning these staple fibers, no operational trouble occurred.

COMPARATIVE EXAMPLE To the same copolyester filament bundle as in Example 7, 0.9% by weight of an oiling agent of the following composition generally used for polyester filaments was, applied, in theform of a emulsion:

Percent Mineral oil (80-90) 60- Turkey red oil 17.5 Triethanolamin oleate 20 Diethylene glycol 2.5

Then the filament bundle was allowed to stand at room temperature for 24 hours to dry. Then the filament bundle was super-drawn at a draw ratio of 3 in hot water maintained at 98 C. At the super-drawing, meltadhesion was caused to occur among mono-filaments and the filament bundle seemed as it it were one monofilament, and the K value of the resulting super-drawn filament bundle was 0.83. The section of the filament bundle is shown in a scanning electromicroscopic photograph of FIG. 2. Then this filament bundle was subjected to the ordinary drawing accompanied by orientation at a draw ratio of 4.5 in a bath of water maintained at 80 C. The state of the melt-adhesion among filaments was a little improved, but after the filament bundle was cut into about 51 mm. staple fibers and opened by means of a fiber opener, neps were brought about in greater portions of the resulting staple fibers and complete opening of such staple fibers was impossible.

What we claim is:

1. A process for the preparation of synthetic linear polyester filament bundles substantially free of melt-adhesion among filaments and Without any substantial molecular orientation, whereby undrawn, substantially amorphous synthetic linear polyester filaments obtained by melt-spinning a synthetic linear polyester in which at least 80 mole percent of the recurring units are ethylene terephthalate units, and up to 20 mole percent of recurring units derived from copolymerizable monomers selected from one or more of dibasic acids selected from adipic acid, sebacic acid, isophthalic acid, diphenyl dicarboxylic acid and naphthalene dicarboxylic acid; oxy acids selected from oxybenzoic acid; and glycols selected from diethylene glycol, propylene glycol, neopentyl glycol, pentaerythritol and polyethylene glycol monomethyl ether, are superdrawn thereby making the filament size finer only morphologically without any substantial orientation; which com- 12 prises applying to the undrawn filaments a compound of the following formula: 7

O 1 Br- 0A-C Rz wherein A represents a group CH i (CHzCHzOl (0112650) CH: [(CH2CHZO)n(CHflH0)in]p in which n, m and p each are integers not less than 1; R is an alkyl, aralkyl or alkylaryl group of 2-26'carbon atoms, and R which may be the same as or diiferentfrom R represents an alkyl, aralkyl or alkylaryl group of 2-26 carbon atoms, in an amount of at least 0.05% by weight based on the weight of the filaments; drying the filaments; and thereafter superdrawing the filaments at a temperature of 98 C. to 160 C. at a draw ratio of -5000%.

2. The process of claim 1 wherein an aqueous solution of at least said compound at a concentration of 0.l20% by weight is applied to said filaments.

References Cited UNITED STATES PATENTS Calvert 260-410.6

ROBERT F. WHITE, Primary Examiner J. B. LOWE, Assistant Examiner US. Cl. X.R.

264290 T, DIG. 73 

